Simplify the following expression: ${3(-7+3n)-(-5n-2)}$
Solution: Distribute the ${3}$ into the first set of parentheses: $ {3(}\gray{-7+3n}{)} - (-5n-2) $ $ {-21+9n} - (-5n-2) $ The minus sign in front of the parentheses means we multiply each term inside the parentheses by ${-1}$ $ -21+9n {-1(}\gray{-5n-2}{)} $ $ -21+9n + {5n+2} $ Rewrite the expression to group the ${n}$ terms and numeric terms: $ {9n + 5n} {-21 + 2}$ Combine the ${n}$ terms: $ {14n} {-21 + 2}$ Combine the numeric terms: $ {14n} {-19}$ The simplified expression is $14n-19$